In scanning microscopy, a specimen is scanned with a light beam. Lasers are often used as the light source for this purpose. An arrangement having a single laser which emits several laser lines is known, for example, from EP 0 495 930, “Confocal microscope system for multi-color fluorescence.” Mixed-gas lasers, in particular ArKr lasers, are usually used at present for this purpose.
Diode lasers and solid-state lasers are also in use.
U.S. Pat. No. 5,161,053 entitled “Confocal microscope” discloses a confocal microscope in which light of an external light source is transported with the aid of a glass fiber to the beam path of the microscope and the end of the glass fiber serves as a point light source, so that a mechanical stop is superfluous.
The emission spectrum of lasers is confined to a narrow wavelength range, so that for simultaneous multiple-line excitation, the light of several lasers must be combined into one illumination beam.
The gas lasers usually used as multiple-line lasers are very complex and expensive. They moreover require a great deal of maintenance, making them difficult to use continuously in many microscopy applications.